Sexual disorders, such as erectile dysfunction and female sexual arousal disorder, are common in human populations and are strongly associated with increased anxiety and depression. Although substantial progress has been made in understanding and treating peripheral and organic causes of these disorders, much less is known about pathological changes in sexual arousal or "libido." To generate attraction and preference for mates, human and non-human animals must integrate signals about their reproductive state (gonadal steroid hormones) with perception of social cues (often odors or pheromones). This proposal will identify and characterize the neural substrates underlying steroidal and chemosensory interaction on attraction and preference for female odors in male golden hamsters, a model organism whose sexual behavior is critically dependent on both social odors and hormones. The experiments will test the hypothesis that steroid-sensitive elements of the medial amygdala (MA) and bed nucleus of the stria terminalis (BNST) mediate the modulatory and permissive effects of gonadal steroids on attraction and preference, whereas chemosensory regions of MA and BNST mediate the evaluative processes underlying preference for female odors. Using behavioral techniques, excitotoxic lesions and electrophysiological recordings in awake, behaving animals, this hypothesis will be tested by determining whether (a) lesioning steroid-sensitive or chemosensory MA and BNST regions impairs sexual attraction and preference, (b) the firing responses of individual neurons and populations of neurons within chemosensory and steroid-sensitive regions of MA and BNST differ in their response specificity to female odors and (c) disconnecting these chemosensory and steroid-sensitive region impairs preference and attraction and changes neural activity within these structures. This data will provide novel insights into how sexual attraction and preference is generated by the nervous system and how sensory and internal state cues interact to regulate motivated behavior.